High pressure billet extruder

ABSTRACT

A set of first hydraulic rams pressurize hydraulic fluid surrounding the jacket of a billet-containing pressure vessel to an intermediate level. A set of second hydraulic rams advance a die ram into the pressure vessel against the nose of the billet to extrude the same, and simultaneously further pressurize the hydraulic fluid surrounding the jacket from the intermediate level to a higher level sufficient to fully withstand high internal pressure in the pressure vessel.

United States Patent Fuchs, Jr. Dec. 10, 1974 [5 HIGH PRESSURE BILLET EXTRUDER 3,531,966 10/1970 Pappas 72/63 3,548,625 12 1970 F h J 72 6O [75] Inventor: Francis Joseph Fuchs, Jr., Princeton 3,563,080 211971 Z Z Z et aL 72;) Junction, NJ. 3,602,024 8/1971 Sabroff et al. 72/60 A ig Western ec i C p y I PlgOtt et al. Incorporated, New York, NY.

Primary ExaminerRichard J. Herbst [22] 1974 Attorney,Agent, or Firm-Jack Schuman [21] Appl. No.: 450,910

Related US. Application Data [57] ABSTRACT [62] Division of Sen 339,457 March 1973 A set of first hydraulic rams pressurize hydraulic fluid abandoned surrounding the jacket of a billet-containing pressure vessel to an intermediate level. A set of second hy- [52] 1.1.8.61 72/60, 72/272 draulic rams advance a die ram into the pressure lit. l. Se] against the nose of the to extrude the Same [5 Fleld of Search 63, and Simultaneously further pressurize the hydraulic fluid surrounding the jacket from the intermediate [56] References C'ted level to a higher level sufficient to fully withstand high NITED STATES PATENTS internal pressure in the pressure vessel.

3,224,042 l2/l965 Meissner t. 3,364,717 1/1968 Green 72/60 7 Clam, 9 Drawmg PATENIEDHEMOIQM 3,852,986

saw u 4 HIGH PRESSURE BILLET EXTRUDER This is a division, of application Ser. No. 339,457 filed Mar. 8, I973, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates, broadly speaking, to an apparatus and method for deforming material. More specifically, this invention relates to an apparatus and method for extruding a discrete billet of material from a highly pressurized chamber.

2. Description of the Prior Art U.S. Pat. No. 3,427,843 (1969) to Green shows a segmented pressure vessel covered with a fluid impermeable sheath. Pressurized fluid is applied to the interior of the vessel to perform a metal working operation therein. Pressurized fluid, which may be from the same body of fluid as the fluid within the vessel, or alternatively from another separate body of fluid, is applied externally to the sheath to hold together the segments of the vessel. A similar disclosure is found in U.S. Pat.

No. 3,364,717 (I968) to Green.

SUMMARY OF THE INVENTION One of the objects of this invention is to provide improved apparatus and method for deforming material.

Another of the objects of this invention is to provide improved apparatus and method for extruding a discrete billet of material from a highly pressurized chamber.

Still other and further objects of this invention will become apparent during the course of the following description and by reference to the accompanying drawings and the appended claims.

Briefly, I have discovered that the foregoing objects may be attained by providing first means to pressurize hydraulic fluid surrounding the jacket of a billetcontaining pressure vessel to an intermediate level, and by providing second means to advance a die ram into the pressure vessel against the billet therein, said second means simultaneously further pressurizing the hydraulic fluid surrounding the jacket of the pressure vessel from the intermediate level to a higher level sufficient to fully withstand high internal pressure in the pressure vessel.

BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings, in which like numerals represent like parts in the several views:

FIG. 1 represents a medial longitudinal section of the apparatus, taken along the line ll of FIG. 2;

FIG. 2 represents an end elevation of the front of the apparatus as viewed from the left of FIG. 1;

FIG. 3 represents a section taken along the line 3-3 of FIG. 2;

FIG. 4 represents a section taken along the line 4-4 of FIG. 1;

FIG. 5 represents an enlarged detail, partially in section, of the rear of the apparatus, viz., the right end of the apparatus as viewed in FIG. 1;

FIG. 6, represents an enlarged detail of the annular check valve at the forward end of the annular piston;

FIG. 7 represents asection taken along the line 7-7 of FIG. 5;

FIG. 8 represents an enlarged detail of the fluid passageway communicating between the chamber receiving the annular piston and the jacket chamber;

FIG. 9 represents a section taken along the line 99 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Extruder l is seen as comprising pressure vessel 2, die ram 3, die ram support means 4, first hydraulic rams 5 and second hydraulic rams 6.

Pressure vessel 2 comprises a plurality of wedgeshaped segments 7 arranged, as shown, as a series of rings forming a pressure chamber 8 mounted within cylinder 9. Plug 10 mounted in the rear of cylinder 9, and held in position by means hereinafter to be described, supports the rear of the pressure chamber 8. A circular plate 11, having seal 12 slidably receiving die ram 3, is placed adjacent the front-most segments 7, and threaded plug 13 mounted in the front of cylinder 9 supports, through plate 11, the front of pressure chamber 8.

A jacket 14, having a circular transverse cross section, is mounted in closely fitting relationship above pressure chamber 8, engaging the entire outer periphery thereof and extending from end to end thereof, sealed at the ends to plug 10 and plate 11 by means of seals 15, which may be O-rings, mounted in recesses 16 in the said plug 10 and plate 11.

A jacket 17, having a circular transverse cross section, is mounted in closely fitting relationship within pressure chamber 8, engaging the entire inner periphery thereof and extending from end to end thereof.

The outer diameter ofjacket 14 is less than the inner diameter of cylinder 9, thereby to provide therebetween a space constituting a jacket chamber 18.

Plug 10 is seen as comprising a shaft portion 19 terminating in a'flange portion 20 having the hereinabove mentioned recess 16 receiving seal 15, the said flange portion 20 abutting the rear of the rearmost wedgeshaped segments 7 and the rear of jacket 14.

Shaft portion 19 extends beyond the rear of cylinder 9, having a circular transverse cross section adapted to function as a guide element, as hereinafter described.

The forward portion of plug 10 has a female threaded opening 21 threadedly receiving billet-supporting plug 22. An opening 23 is provided in plug 10 communicating between the threaded opening 21 and the rear of the plug 10.

Cylinder 9 is provided'with a female threaded opening 24 threadedly receiving retaining element 25 having a recess 26 formed therein in turn receiving sleeve 27.

The inner surface of sleeve 27 is spaced from the outer surface of the forward portion of shaft portion 19 sufficiently to provide therebetween an annular cylindrical chamber 28. Radially disposed slots 29 are provided at the rear face of flange portion 20 communicating between chamber 28 and chamber 30 formed in cylinder 9 about the periphery of flange portion 20, the said chamber 30 communicating with jacket chamber 18.

Retaining element 25 is provided with a recess 31 in which seal 32, which may be an 0-ring, is mounted.

Billet-supporting plug 22 has a flat nose 33 extending into pressure chamber 8, slidably engaging the inner surface of jacket 17, and provided with recess 34 in which a seal 35, which may be an O-ring, is mounted, whereby to seal the rear of pressure chamber 8.

Driving member 36 is provided at its forward end with annular piston 37 which is slidably received in chamber 28 between sleeve 27 and shaft portion 19 of plug 10.

Driving member 36 has a chamber 38 provided with a threaded female opening 39 at the rear thereof, and a passageway 40 therethrough communicates between the said chamber 38 and the forward end of annular piston 37. Radially spaced from passage 40, and extending from front to rear of driving member 36, is a vent passageway 40a which communicates between the forward end of annular piston 37 and the atmosphere. Ring 41 is provided adjacent the forward end of annular piston 37, with a plurality of apertures 42 radially spaced thereabout. Threaded elements 43, having enlarged heads 44, slidably extend through the apertures 42 and are threadedly mounted in female threaded openings 45 radially spaced about the front end of annular piston 37. Springs 46 are mounted in compression between enlarged heads 44 and ring 41, thereby to resiliently urge ring 41 against the forward end of annular piston 37. Clearance is provided between the inner and outer peripheral surfaces of ring 41 and the adjacent walls of chamber 28, whereby to permit the passage of fluid between the said ring 41 and the walls of chamber 28. As will hereinafter be described, ring 41 constitutes a check valve operative against passageways 40 and 40a.

A seal 47 is provided in the recess 26 of retaining ele-j ment 25 at the rear end of sleeve 27. A recess 48 is provided in the shaft portion 19 of plug 10, andseal 49 is mounted therein opposite seal 47. Seals 47 and 49 may be O-rings.

Driving member 36 has a central longitudinal opening 50 extending therethrough, the wall 51 of said opening having a circular transverse cross section slidably received on shaft portion 19 and guided thereby for longitudinal sliding reciprocable movement.

Driving member 36 has an apertured flange 52 extending forwardly thereof to which are secured first and second hydraulic rams and 6.

Plate 53 is mounted to the forward end of pressure vessel 2.

The piston rods 54 of first hydraulic rams 5 extend through apertures 55 in plate 53 and terminate in threaded ends receiving nuts 56 which bear on the forward face of plate 53.

The cylinders of each of the first hydraulic rams 5 have ports 57 and 58 connectable to a source of pressurized hydraulic fluid (not shown). It will be evident that, when pressurized hydraulic fluid from the source thereof is introduced simultaneously into all ports 57 serving the rod side of the pistons in the cylinders of first hydraulic rams 5, driving member 36 will be pulled toward pressure vessel 2, thereby forcing annular piston 37 into chamber 28 and pressurizing extrusion fluid therein, the said pressure being communicated through slots 29 and chamber 30 to jacket chamber 18.

Plate 53 is provided with recesses 59 extending radially inwardly from the periphery thereof.

The cylinders of second hydraulicrams 6 are seated within recesses 59, and the piston rods 60 of the said second hydraulic rams 6 extend through apertures in ears 61 of yoke 62, terminating in threaded ends receiving nuts 63 which bear on the forward faces of ears 61.

The cylinders of each of the second hydraulic rams 6 have ports 64 and 65 connectable to a source of pressurized hydraulic fluid (not shown).

Die ram 3 comprises die 66 mounted on die stem 67. Aperture 68 extends longitudinally through die stem 67.

Die ram 3 extends in a slidably sealed manner through seal 12 and slidably engages the inner periphery of jacket 17 for longitudinal reciprocation relative thereto.

Die ram support means 4 comprises guide cylinder 69 mounted to plate 53, aligning plates 70 longitudinally slidably received in the bore of guide cylinder 69 and having central apertures slidably receiving die ram 3. Bolts 71, constituting a lost-motion linkage mechanism, are mounted between aligning plates 70 in the manner shown and described in my US. Pat. No. 3,548,625 (1970) entitled Collapsible Feed Mechanism. The principle of operation of die ram means 4 in the present invention is the same as described in US. Pat. No. 3,548,625. Briefly, the purpose of die ram support means 4 is to provide lateral support at spaced lengths along die ram 3 which, in the absence of such lateral support, will be a compressibly loaded slender member and subject to buckling. When die ram 3 is in its retracted position (i.e., its left-most position as viewed in FIG. 1 aligning plates 70 are separated from each other and uniformly spaced along the length of die ram 3 in laterally supporting relationship thereto. As die ram 3 is advanced, under axial compression, into pressure chamber 8, the front-most aligning plates 70 advance to the right of FIG. 1 and engage and carry along to the right successive aligning plates 70. FIG. 1 shows die ram 3 in an intermediate position with about half of the aligning plates 70 collapsed. When die ram 3 is returned, at the end of an extrusion cycle, from its right-momst to its left-most (as viewed in FIG. 1) position, bolts 71 carry their respective aligning'plates 70 to their proper positions longitudinally of die ram 3. The details of die ram support means 4 (viz., the mounting of bolts 71 between aligning plates 70, are

clearly and fully described in US. Pat. No. 3,548,625

to which reference should be made, and form no part of the present invention.

Yoke. 62 comprises cylinder 72 to which ears 61 are secured in radially extending relationship thereto. The bore 73 of cylinder 72 slidably engages the outer periphery of guide cylinder 69. Retaining ring 74 is threadedly mounted to the end of cylinder 72, and thrust sleeve 75 is positioned within bore 73 of cylinder 72, flange 76 thereof abutting retaining ring 74. The outer periphery of thrust sleeve 75 slidably engages the bore 77 of guide cylinder 69. It will beseen that cylinder 72 and thrust sleeve 75 are reciprocable relative to guide cylinder 69,in sliding engagement therewith and guided thereby, upon activation of second hydraulic rams 6. The spacing between flange 76 and the end 78 of guide cylinder 69 is sufflcient to permit die 66 to travel to a position adjacent the rear end of pressure chamber 8.

Supporting plug 79 is threadedly mounted to the end of thrust sleeve 75, and the end of die stem 67 is mounted thereto in abutting relationship as shown. Supporting plug 79 also abuts the end of the rearmost aligning plate 70a. Supporting plut 79 is provided with aperture 80 registering with 68 of die stem 67.

Retaining ring 74 and thrust sleeve 75 are provided with bores 81 permitting access to supporting plug 79.

Stop means are provided to limit the stroke of yoke 62, and comprises a pair of clamps 82 each having a curved inner surfaces 83 with a radius of curvature equalling the radius of guide cylinder 69, a pair of brackets 84 secured in a suitable manner to plate 53 and a pair of links 85 pivotally mounted at 86 and 87 between each clamp 82 and its respective bracket 84. It will be seen, from FIG. 2, that clamps 82 can be swung between an inoperative position shown in phantom, in which inoperative position clamps 82 are disengaged from guide cylinder 69 and are entirely clear of the path of yoke 62, to an operative position shown in solid lines in FIG. 2, in which operative position clamps 82 engage guide cylinder 69 and are interposed in the path of yoke 62 between the said yoke 62 and plate 53. The width of clamps 82 is chosen so that yoke 62 will abut clamps 82 when die 66 has travelled to the right of FIG. 1 to a position just to the left of flat nose 33 of billet-supporting plug 22. Thus, visible means are provided outside of the apparatus to indicate the completion of an extrusion cycle and to avoid overtravel of die 66 against flat nose 33 which could damage the apparatus. When it is desired to clear pressure chamber 8 or to replace die 66, clamps 82 are swung to the inoperative position shown in phantom outline in FIG. 2, billetsupporting plug 22 is unthreaded from plug and removed through opening 50 of driving member 36, and yoke 62 is advanced until it abuts plate 53 at which point die ram 3 will have been advanced sufficiently to the rear of pressure chamber 8, to the right of FIG. 1, as to project die 66 at least into opening 50 whence it the contents of pressure chamber 8 may be removed and/or die 66 may be removed and replaced.

It will be apparent from the foregoing description that yoke 62, plate 53 and driving member 36 move relatively to each other during operation of the apparatus. Advantageously, driving member 36 may be secured on a plate suitable pedestal or mount 88. Yoke 62 and plate 53 may each be mounted on a bracket 89 provided with apertured ears 90 slidably receiving guide rods 91 which latter are supported in any suitable manner (not shown). During operation of apparatus 1, yoke 62 and plate 53 will move toward driving member 36, guided and supported in their respective movements on guide rods 91.

The operation of extruder 1 will now be described. With annular piston 37 in retracted position (i.e., the forward end thereof is in its right-most position in chamber 28 as shown in FIG. 5), jacket chamber 18 is filled with a suitable supporting fluid which, advantageously, may be an hydraulic oil. This may be done by threading into opening 39 a conduit 92 which communicates with a source (not shown) of hydraulic oil. In

such manner, hydraulic oil is forced under pressure into chamber 38 and thence through passageway 40 against the rear of ring 41. Under the influence of the pressurized hydraulic oil, ring 41 is displaced forwardly and away from the front end of annular piston 37, against springs 46, thereby uncovering the forward ends of passageways 40 and 40a. Some of the hydraulic oil will pass out through passageway 40a, and some of the hydraulic oil will enter'chamber 28, and then pass through slots 29 into chamber 30 and thence into jacket chamber 18. Air vented from jacket chamber 18 will exit extruder 1 through passageway 40a.

When the pressure in jacket chamber 18 reaches the pressure of hydraulic oil in conduit 92, ring 41, under the influence of springs 46, will be forced against the forward end of annular piston 37 to close passageways 40 and 40a therein.

Clamps 82 are swung inwardly to the solid-line position shown in FIG. 2, thereby to engage guide cylinder 69.

Billet-supporting plug 22 is removed from opening 11 of plug 10. Billet 93 and a suitable extrusion mediuim are introduced into pressure chamber 8. Advantageously, the nose at the forward end of billet 93 may be shaped in the known manner to correspond with the profile of die 66. The extrusion medium may be a fluid such as castor oil, or may be a normally solid low shear strength material such as low density polyethylene wax. In the latter case, the wax may be employed in the normally solid state or may be employed at an elevated temperature sufficient to liquefy the wax. Electrical heating elements (not shown) of conventional design may be provided in cylinder 9 for this latter purpose.

After pressure chamber 8 has received the billet 93 and the extrusion medium, billet-supporting plug 22 is inserted in opening 11 of plug 10.

The rod sides of the cylinders of first hydraulic rams 5 are simultaneously pressurized through ports 57, thereby advancing pressure vessel 2 toward driving member 36. In such manner, annular piston 37 travels toward the forward end of chamber 28, pressurizing the hydraulic oil therein which increase in pressure is transmitted through slots 29 and chamber 30 to the hydraulic oil in jacket chamber 18. The pressure in jacket chamber 18 is increased, in the manner hereinabove described, to a level sufficient to provide adequate initial support to wedge-shaped segments 7 prior to commencing extrusion of the billet 93.

Thereafter, the rod sides of the cylinders of second hydraulic rams 6 are simultaneously pressurized through ports 94, thereby advancing yoke 62 toward pressure vessel 2 and, simultaneously, pressure vessel 2 toward driving member 36. Thus, die ram 3 is advanced into pressure chamber 8 against the nose of billet 93, resulting in a rise in pressure within pressure chamber 8 to a peak value at which point extrusion of billet 93 actually commences, the internal pressure in pressure chamber 8 then dropping from the peak value to a run-out or equilibrium value during the actual extrusion of billet 93. At the same time annular piston 37 is advanced further toward the forward end of chamber 28 thereby to further increase the pressure in jacket chamber 18 to the level required to support wedgeshaped segments 7 against the pressure in pressure chamber 8. The pressure in jacket chamber 18 will rise to a peak value simultaneously with the peak value in pressure chamber 8, and will fall to steady state or equilibrium value simultaneously with the drop in pressure in pressure chamber 8 from the peak value to the runout or equilibrium value.

The problems of peak extrusion pressure and solutions to the problem are described in my pending patent application Ser. No. 265,219 filed June 22, 1972, and entitled Method of and Means for Commencing a Deformation Operation, e.g., Hydrostatic Extrusion of a Billet; in my pending patent application jointly filed on June 22, 1972, with P. S. Venkatesan, Ser. No. 265,165 and entitled Method of and Means for Commencing a Deforming Operation, e.g., Hydrostatic Extrusion of a Billet;" in my pending patent application jointly filed on June 22, 1972, with P. S. Venkatesan, Ser. No. 266,143 and entitled Method of and Means for Commencing a Deforming Operation, e.g., Hydrostatic Extrusion of a Billet; and in my pending patent application jointly filed on June 22, 1972, with P. S. Venkatesan, Ser. No. 265,245 and entitled Method of 'and Means for Commencing a Deforming Operation,

e.g., Hydrostatic Extrusion of a Billet.

When extrusion of billet 93 commences, the resulting wire 94 travels from die 66 through aperture 68 in die ram 3 and through aperture 80 of supporting plug 79 and exits extruder 1 through the front thereof whence the said wire 94 may be collected in any suitable manner.

During the extrusion of billet 93, there is a flow of the extrusion medium through the zone of deformation of the die 66 between the said die 66 and the nose of billet 93 in the manner generally described in my U.S. Pat. No. 3,677,048 (1972).

The extrusion of billet 93 is continued until yoke 62 abuts clamps 82, signifying that die 66 abuts the forward end of billet supporting plug 20, whereupon ports 64 are disconnected from the pressurized source of hydraulic fluid operating second hydraulic rams 6 to terminate the extrusion cycle.

When it is desired to remove from pressure chamber 8 any remaining portion of billet 93, or to remove and replace die 66, the pressures in pressure chamber 8 and jacket chamber 18 are relieved (e .g., by permitting hydraulic fluid in the rod ends of the cylinders of first and second hydraulic rams and 6 to vent through ports 57 and 64, respectively, back to a sump serving the source of hydraulic fluid). Billet supporting plug 22 is removed from opening 21, and clamps 82 are swung away from guide cylinder 69 to the position shown in phantom outline in FIG. 2, thereby clearing the. path of yoke 62. Second hydraulic rams 6 are now pressurized through ports 64, thereby to advance yoke 62 and die ram 3 sufficiently to eject any billet remnant from the rear of pressure chamber 8 through opening 21 and/or to extend die 66 into or beyond said opening 2] whence the said die 66 may be removed and replaced.

Extruder 1 has been operated experimentally in the laboratory, and pressures in excess of 400,000 psi have been generated in the pressure chamber 8.

In a typical cycle of extrusion of a copper billet, wherein a low density polyethylene wax was employed as the extrusion medium, the following data were noted:

Billet diameterapproximately 5/16 inch.

Pressure chamber heated to 200 F.

Peak pressure in pressure chamber-318,000 psi.

Run-out pressure in pressure chamber, during extrusion280,000 psi.

Peak pressure in jacket chamber-67,000 psi.

Steady state pressure in jacket chamber, during extrusion-55,000 psi.

Wire diameter-approximately 0.016 inch.

Velocity of extrusion of wire-4,000 feet/minute.

It will be clear from the foregoing specification that, in my extruder 1, l have provided a means for pressurizing the fluid jacket surrounding a pressure chamber which eliminates the time lag which heretofore has been encountered in pressurizing the fluid jacket.

What is claimed is:

1. Apparatus for extruding a billet, said apparatus comprising:

a. an extrusion chamber adapted to receive said billet and extrusion medium;

b. a jacket chamber surrounding said extrusion chamber and adapted to receive hydraulic fluid to provide external support to said extrusion chamber against internal pressure developed therein;

c. pressurizing means communicating with said jacket chamber and adapted to pressurize the hydraulic fluid therein;

d. first means connected to said pressurizing means and adapted to operate said pressurizing means to pressurize the hydraulic fluid in said jacket chamber to a first level;

e. a die;

f. second means connected to said pressurizing means and adapted to pressurize said extrusion medium and extrude said billet through said die and simultaneously to operate said pressurizing device to increase the pressure of the hydraulic fluid in said jacket chamber from said first level to a second level sufficient to externally support said extrusion chamber against internal pressure developed therein. 7

2. Apparatus as in claim 1, wherein:

g. said first means comprises hydraulic ram means operatively connected at one end to said extrusion chamber.

3. Apparatus for extruding a billet, said apparatus comprising:

a. an extrusion chamber adapted to receive said billet and extrusion medium;

b. a jacket chamber surrounding said extrusion chamber and adapted to receive hydraulic fluid to provide external support to said extrusion chamber against internal pressure dei0hssn c. pressurizing means including piston means communicating with said jacket chamber and adapted to pressurize the hydraulic fluid therein upon advancement of said piston means;

d. first means connected to said piston means and adapted to advance said piston means to pressurize the hydraulic fluid in said jacket chamber to a first level;

e. a die;

f. second means connected to said piston means and operatively interposed between said piston means and said die, said second means being adapted to advance said die into said extrusion chamber and against said billet to pressurize said extrusion medium and extrude said billet through said die and simultaneously to further advance said piston means to increase the pressure of the hydraulic fluid in said jacket chamber from said first level to a second level sufficient to externally support said extrusion chamber against internal pressure developed therein.

4. Apparatus as in claim 3, wherein:

g. said first means comprises hydraulic ram means operativelyconnected at one end to said extrusion chamber.

5. Apparatus for extruding a billet, said apparatus comprising:

a. a pressure vessel having:

i. an extrusion chamber therein adapted to receive said billet and extrusion medium;

ii. a jacket chamber surrounding said extrusion chamber and adapted to receive hydraulic fluid to provide external support to said extrusion chamber against internal pressure developed therein;

iii. a pressurizing cylinder communicating with said jacket chamber and adapted to receive hydraulic fluid;

b. a piston slidably mounted within said pressurizing cylinder;

c. first hydraulic ram means connected at one end to said pressure vessel and connected at the other end to said piston and adapted to advance said piston within said pressurizing cylinder to pressurize the hydraulic fluid in said jacket chamber to a first level;

(1. a die ram;

e. a die mounted on said die ram;

f. second hydraulic ram means connected at one end to said die ram and connected at the other end to said piston and adapted to advance said die ram and said die into said extrusion chamber and against said billet to pressurize said extrusion medium and extrude said billet through said die and simultaneously to further advance said piston within said pressurizing cylinder to increase the pressure of the hydraulic fluid in said jacket chamber from said first level to a second level sufficient to externally support said extrusion chamber against internal pressure developed therein.

6. Apparatus as in claim 5., wherein:

g. said pressurizing cylinder is an annular chamber;

h. said piston comprises an annular member slidably mounted in said pressurizing cylinder.

7. Apparatus as in claim 6, wherein:

i. said piston is provided with a passageway extending to the end of the annular member;

j. check valve means interposed between the end of the annular member and said pressurizing cylinder and adapted to permit the flow of hydraulic fluid in one direction only from said passageway to said Parent No.

lnventor( s) Parent are hereby corrected as shown below:

' IN THE SPECIFICATION:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION FRANCIS JOSEPH FUCHS, JR.

lr is certified that error appears in rhe above-identified parenr and that said Letters (This is a request for a Supplemental Certificate of Correction.)

Column 5-, line 36, "whence it should read --whence.

IN THE CLAIMS 2 Column 8, line L0, "deiOhssn" should read --developed therein;

Signed and Scaled this ninth Day of March 1976 [SEAL] Arrest:

RUTH C. MASON Atlesting Officer C. MARSHALL DANN Commissioner ofPatems and Trademarks L- 566-PT UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Pagan; No. 3, 5 ,9 Dated December 10. B974 lnvemor(s) FRANCIS JOSEPH FUCHS JR.

It is certified that error appears in the above-identified parent and that-said Leners Patent are hereby corrected as shown below:

IN THE SPECIFICATION: I

Column 2, line 2 L "above" should read "about". Column 3, line 12, "passage' should read --passageway-.. Column L,

line 21, "ram means" should read --ram support means----; line LO, "right-momst" should read --right-most--. Column 5, line 1, "plut" should. read --plugline '8, "surfaces" should read "surface-g v I I I f I line L3, "a plate suitable" should read ---a suitable"; Column 6,

line 63, "problems" should read --problem-'-.

IN THE CLAIMS:

Column 8, line 23, I "devieeu should read -means-- I Signed and sealed this 4th day of March 1975.

SEAL) I AttStL C. MARSHALL DANN RUTH C. IEASON I Commissioner of Patents attesting I Officer. I and Trademarks 

1. Apparatus for extruding a billet, said apparatus comprising: a. an extrusion chamber adapted to receive said billet and extrusion medium; b. a jacket chamber surrounding said extrusion chamber and adapted to receive hydraulic fluid to provide external support to said extrusion chamber against internal pressure developed therein; c. pressurizing means communicating with said jacket chamber and adapted to pressurize the hydraulic fluid therein; d. first means connected to said pressurizing means and adapted to operate said pressurizing means to pressurize the hydraulic fluid in said jacket chamber to a first level; e. a die; f. second means connected to said pressurizing means and adapted to pressurize said extrusion medium and extrude said billet through said die and simultaneously to operate said pressurizing device to increase the pressure of the hydraulic fluid in said jacket chamber from said first level to a second level sufficient to externally support said extrusion chamber against internal pressure developed therein.
 2. Apparatus as in claim 1, wherein: g. said first means comprises hydraulic ram means operatively connected at one end to said extrusion chamber.
 3. Apparatus for extruding a billet, said apparatus comprising: a. an extrusion chamber adapted to receive said billet and extrusion medium; b. a jacket chamber surrounding said extrusion chamber and adapted to receive hydraulic fluid to provide external support to said extrusion chamber against internal pressure dei0hssn c. pressurizing means including piston means communicating with said jacket chamber and adapted to pressurize the hydraulic fluid therein upon advancement of said piston means; d. first means connected to said piston means and adapted to advance said piston means to pressurize the hydraulic fluid in said jacket chamber to a first level; e. a die; f. second means connected to said piston means and operatively interposed between said piston means and said die, said second means being adapted to advance said die into said extrusion chamber and against said billet to pressurize said extrusion medium and extrude said billet through said die and simultaneously to further advance said piston means to increase the pressure of the hydraulic fluid in said jacket chamber from said first level to a second level sufficient to externally support said extrusion chamber against internal pressure developed therein.
 4. Apparatus as in claim 3, wherein: g. said first means comprises hydraulic ram means operatively connected at one end to said extrusion chamber.
 5. Apparatus for extruding a billet, said apparatus comprising: a. a pressure vessel having: i. an extrusion chamber therein adapted to receive said billet and extrusion medium; ii. a jacket chamber surrounding said extrusion chamber and adapted to receive hydraulic fluid to provide external support to said extrusion chamber against internal pressure developed therein; iii. a pressurizing cylinder communicating with said jacket chamber and adapted to receive hydraulic fluid; b. a piston slidably mounted within said pressurizing cylinder; c. first hydraulic ram means connected at one end to said pressure vessel and connected at the other end to said piston and adapted to advance said piston within said pressurizing cylinder to pressurize the hydraulic fluid in said jacket chamber to a first level; d. a die ram; e. a die mounted on said die ram; f. second hydraulic ram means connected at one end to said die ram and connected at the other end to said piston and adapted to advance said die ram and said die into said extrusion chamber and against said billet to pressurize said extrusion medium and extrude said billet through said die and simultaneously to further advance said piston within said pressurizing cylinder to increase the pressure of the hydraulic fluid in said jacket chamber from said first level to a second level sufficient to externally support said extrusion chamber against internal pressure developed therein.
 6. Apparatus as in claim 5, wherein: g. said pressurizing cylinder is an annular chamber; h. said piston comprises an annular member slidably mounted in said pressurizing cylinder.
 7. Apparatus as in claim 6, wherein: i. said piston is provided with a passageway extending to the end of the annular member; j. check valve means interposed between the end of the annular member and said pressurizing cylinder and adapted to permit the flow of hydraulic fluid in one direction only from said passageway to said pressurizing cylinder. 